The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Shifting and torque converter clutch lockup are adjusted by a controller based on data from input sensors and switches. The electronic system controls these operations using solenoid-operated valves. This control approach improves drivability. With electronic control, information about the engine, fuel, ignition, vacuum, and operating temperatures is used to ensure that shifting and converter lockup take place at the right time.
Many conventional control systems allow the controller to change the behavior of the transmission or torque converter in response to learned information such as typical operating conditions and habits of the driver. The system monitors the conditions of the engine and compensates for any changes in the engine's performance. The controller also monitors the typical driving style of the driver and adjusts the timing of shifts and converter lock-up to provide smooth shifting at the appropriate time. The electronic system is constantly learning about the vehicle and the driver. The controller adapts its normal operating procedures to best meet the needs of the vehicle and the driver. These electronic systems are said to have adaptive learning capabilities. To store this adaptive learning information, the controller may include long-term adaptive memory.
One form of adaptive learning strategy involves adapting a pressure value supplied to an electronically controlled converter clutch (ECCC). Conventional ECCC adapt systems learn adaptive pressure values over time based on engine torque conditions commanded by the driver. If the driver spends a considerable amount of time at low engine torque conditions, the adaptive values for higher engine torque conditions may not be learned at all. This creates a disparity in the adapted values that can adversely impact control of the TCC when transitioning from low to high engine torque conditions. The disparity has been corrected by a pressure value added to or subtracted from the adapt value to prevent over pressurization (lock) or under pressurization (flare).